1. Field of the Invention
This invention relates to novel quaternized, dye-complexable N-vinylpyridine carboxylate polymers, and to the process for their preparation involving water based polymerization of N-vinyl pyridine monomer and subsequent quaternization of the resulting vinyl pyridine polymer emulsion.
2. Description of the Prior Art
Dye complexing polymers have been used in laundry detergent and fabric softener compositions to stabilize and minimize leaching of dyes in colored fabrics. During washing of colored and white fabrics, some of the dyes can bleed out of a colored fabric and a portion of the leached dye may deposit on white or lighter colored fabrics. The degree of bleeding is influenced by the character of the dye, the type of cloth and the pH, temperature and mechanical efficiency of the agitation process. Although in some cases the bled dye in the wash liquor can be washed off without altering the color of lighter colored fabrics, the dyed fabric looses a degree of brilliance resulting in a somewhat faded appearance. Often it is found that the fugitive dye deposits either onto the same fabric or onto another fabric leading to patches and streaks in the washed material. This deposition of the bled dye can be inhibited in several ways. One method involves the use of a dye transfer inhibitor (DTI) compound which can complex with the dye and minimize leaching or at least prevent redeposition on the same or other fabrics.
Polyvinylpyrrolidone (PVP), by virtue of its dye complexation ability, has been used to inhibit dye deposition during washing of colored fabrics under laundry conditions. The performance of PVP as a DTI, however, is adversely affected by the presence of anionic surfactants usually present in the washing process.
Vinylpyridine polymers such as those disclosed in U.S. Pat. No. 4,824,910 and in our previous U.S. patent application Ser. No. 932,448, now U.S. Pat. No. 5,776,879, were formerly synthesized in alcoholic media; however, the product of this process contains significantly high unreacted monomer for a given period of reaction time and requires separation of organic solvent to recover pure polymer product. Costly and time consuming treatments are employed to remove impurities with the organic solvent in order to recover a purified product having no objectionable color.
Accordingly, it is an object of this invention to provide quaternized, complexable vinyl pyridine carboxylate polymers and an improved process for the preparation of the non-quaternized polymers, subsequent to their quaternization, which are soluble in water.
Another object is to provide an economical and commercially feasible process for the preparation of a water soluble dye transfer inhibitor and agrochemically or pharmaceutically complexable polymers, which are obtained in high purity suitable for immediate use in formulations.
A further feature of the invention is the provision of a water soluble poly(vinylpyridine polymer) containing a quaternary nitrogen and a carboxylate salt in high yield and purity.
Another object of the invention is to provide a laundry detergent composition which effectively resists fabric dye transfer during the washing and rinsing cycles, even in the presence of anionic surfactants. These and many other benefits and advantages of this invention will become apparent from the following description and disclosure.